1. Field of the Invention
This disclosure relates to a cartridge configured to be demountably mounted to an electrophotographic image forming apparatus (hereinafter, referred to as “image forming apparatus”).
The image forming apparatus is configured to form an image on a recording medium by using an electrophotographic system. Examples of the image forming apparatus include copying machines, printers (for example, laser beam printers, and LED printers), facsimile apparatuses, and word processors.
The cartridge relates to a developing cartridge which is an integral cartridge including a developing device used for developing an electrostatic latent image on an electrophotographic photosensitive member and a process cartridge which is an integral cartridge including at least one of a charging device, a developing device, and a cleaning device which correspond to process devices and an electrophotographic photosensitive member which corresponds to an image bearing member (hereinafter, referred to as “photosensitive drum”). The developing cartridge and the process cartridge are demountably mounted on the image forming apparatus.
2. Description of the Related Art
An image forming apparatus is configured to charge a photosensitive drum which corresponds to an image bearing member uniformly and form a latent image by selective exposure of the photosensitive drum to light. The latent image is developed by a developing agent (hereinafter, referred to as “toner”), and is visualized as a toner image. Then, the toner image is transferred to a recording medium.
The toner image is fixed to the recording medium by applying the transferred toner image with heat or pressure, whereby the image is recorded. In the related art, the image forming apparatus in this configuration is subjected to a toner supply or maintenance of various process devices.
As devices to facilitate the toner supply work or the maintenance, a cartridge system in which all or part of the devices such as the photosensitive drum, a charging device, a developing device, and a cleaning device are collectively unified into a cartridge so as to be demountably mountable on the image forming apparatus is employed.
According to the cartridge system described above, the maintenance of the apparatus can be performed by a user by his or her own in a form of replacement of cartridge, and hence operability may dramatically be improved. Therefore, the cartridge system is widely employed in the image forming apparatuses.
The cartridge as described above includes a plurality of members. Examples of known method of fixing the plurality of members in the related art include fixation with screws and fixation with ultrasonic wave welding. As a simplified method, a method of fixing a flexible first engaging portion provided on a first member in a state of being assembled to a second member is known (see Japanese Patent Laid-Open No. 2010-26500). Specifically, the first engaging portion is restricted from being bent by mounting a restriction portion provided on a third member in a state in which the first engaging portion is assembled to the second member in a state of being bent. Accordingly, the first member and the second member are assembled.
In the related art, in order to maintain the state in which the first member and the second member are assembled, a configuration for fixing the third member having the restriction portion which restricts the flexible first engaging portion from being bent is additionally required.
However, when the third member is mounted for restricting the first engaging portion from being bent, rattling may easily result between the first and second members and the third member as the restriction portion due to variations in dimension due to tolerances. In particular, the rattling becomes an issue for positioning of members which require positional accuracy such as that between a developing roller and a developing blade as developing devices or between the photosensitive drum and a cleaning blade as a cleaning device when a flame member and a bearing are fixed.
Accordingly, this disclosure provides a cartridge with little rattling even though there are variations in dimension due to the tolerances with a fixing method using a flexible engaging portion instead of fixation on the basis of screws or ultrasonic welding. Consequently, a cartridge stable in positional accuracy such as that between the developing roller and the developing blade or between the photosensitive drum and the cleaning blade is also provided.